Collection and subsequent analysis of fluid samples is used for monitoring industrial processes, determining properties and dynamics of pharmaceutical, chemical compounds and biological materials in animals and humans and also in natural or artificial systems, for environmental research and surveillance, for monitoring sewage, flowing water in streams and rivers, precipitation.
In medical science and pharmaceutical industry, there is often a need to perform pharmacokinetic studies on living beings, for example test objects such as rats and pigs. In such studies, it is common to take a plurality of samples or specimens from the test object. Also, injecting substances into the test object during the course of hours or days, in order to allow observation of gradual responses in the test object is also common.
Similarly, patient blood chemistry and monitoring of patient blood chemistry are important diagnostic tools in patient care. For example, the measurement of blood analytes and parameters often provide much needed patient information regarding the proper dose and administration time period. Blood analytes and parameters tend to change frequently, however, especially in the case of a patient under continual treatment, thus making the measurement process tedious, frequent, and difficult to manage. Conventional measurement techniques require lancing of a convenient part of the body (normally a fingertip) with a sharp lancet, milking the finger to produce a drop of blood at the impalement site, and depositing the drop of blood on a measurement device (such as an analysis strip). This lancing method is painful, messy and inconvenient for the patient.
In order to minimize the time and cost for manual handling of taking specimen as well as the stress related to such manual handling on the laboratory animal or human subject, attempts have been made at automating the sample taking procedure.
However, most of the existing sampling systems usually suffer from at least one of the following limitations. The systems are not portable and their functioning depends either on gravity or a certain system orientation. Some systems suffer from possible sample carry-over from one sample to subsequent. In others, the sample is diluted with a rinsing fluid but the use of the rinsing fluid to limit carryover from one sample to another also leads to wastage of some sample fluid. In some other systems, the samples require some form of manual treatment such as pipetting, dilution or centrifugation before being introduced into the analysis device. In other systems, the samples require cooling or freezing to minimize possible analyte deterioration. Also, individual samples may be destroyed, lost or contaminated between sampling and analysis and in some systems; the samples are not immediately ready for shipment or storage. Further, a minimum sample volume of typically 50 micro liters is necessary to enable handling of sample in some other systems.
Therefore, there exists a need for a body fluid sampling device that overcomes the limitations of the existing systems and allows portability, continual sampling of the fluids, easy storage and handling and automatic preparation and analysis of the collected sample.